I've got a Fisher Marlin '06 and have recently been taking it on some heavy duty single-tracks, jumps, and what not (not the best idea for a XC, I know). I've recently noticed that the tires seemed to be slightly warped, meaning when the tires rotate the wheel seems to wobble right and left. It's a very small wobble (I'd say about a couple cm if I had to guess). My question is, is this a big problem I need to worry about and if so are their anyways I can repair the tires? I'm fairly new at repairing bikes, but am quick and willing to learn. Thanks in advance.

make sure the tire is on tight.

if it still wobbles, remove the wheel, deflate the tire, remove the tire and the tube. put the rim back on without anything and spin it again. see if the rim needs to be trued(straightened) or rebuild. if it spins freely and true, check your tube for any odd looking things or shapes or deformed parts. do the same with the tire itself. put everything back together.

if you still can't find the prob. i'm down to learn from the real genuises here.

First, it isn't the tire, it's the wheel. The marlin isn't designed to be a jumper. Take it to the lbs and see if they can true the wheel up.

def. the wheels... the stock wheels arent meant to take such hits, and are probably machine made (not hand made) so they are out of true

What? It certainly CAN be the tire- there is such a thing as mis-molded tires.
But, I would say +2 to Alumrock's suggested proceedure.

I don't know if it's the wheel or the tire, but I had the same problem with my front tire a while back. I did basically what alumrock said, i.e., I just deflated the tire, removed and reinserted the tube (after inspection) and inflated it. It worked good as new. Hopefully that'll be all you need to do. I could tell that the problem wasn't the wheel without having to take the tire off, however, because I just held a screwdriver close to the rim and spun the wheel to see if it was out of true, which it wasn't.

one of the benefits of V-Brakes, helps keep the rims true

I've seen tires that wobble to the left and to the right a little, but I'd agree with everyone else, if you're doing jumps with stock wheels they are probably out of true.

It might be tough to eyeball trueness if you have disc brakes. You could try gripping the fork firmly with your hand and pointing your index finger at the rim until its like 1mm or so from the rim. then (while firmly holding your hand in that position) spin the wheel, if it intermittently touches your finger, your rim is out of true.

Since when do v-brakes help keep rims true? Never heard that one used before. From experience, v-brakes make a hinderance if your wheels have come out of true.

I think he means that it forces you to check and maintain the trueness of your wheels, lest you start rubbing. Beween riding a MTB with disks and a brakeless fixie, I've become really bad about checking and truing my wheels.

Thanks for all the tips and tests guys, very big help. My riding has gotten increasingly more stressful for my bike recently and I don't know if I can quite stop myself if I see a nice drop/jump, seesaw, or a couple of rock gardens. I know that the Marlin is not made for this kinda stuff so no need in telling me that again. I was wondering if there's maybe some more durable rims for cheap or any way that I make it to where I still have fun on my bike without beating the hell out of it. I don't really know what to look for in rims so any help will do. Thanks again guys

I'd go with Alumrock's suggestions.
Probably take care of the problem.

From there, to answer your question about better wheels,
A good set of wheels for the type of riding you are describing with drops, jumps, and rock gardens for a good price is definately the Halo Combat wheelset.
Strong enough for what you are doing and at a decent price too. $250 for F and R together, a little more buying seperately.

sweet thanks for the quick reply. I just got back from the LBS and the dude said the rims weren't in need of repair and that my actual tires were at fault. Lesson learned =)

I have an old school aluminum mongoose 26 in 21 speed that I rebuilt several times some used and New parts. I've tought myself to true and then to build wheels. I don't have a truing stand so I made a tool out of an old spoke that wraps around the fork. Take the tire and tube off and replace the wheel.put the tool on the fork so it's as close as I can be without rubbing the wheel. Spin the wheel and with marks put on the tool will show where the center is and where the edges of the rims are. Also since it's just wrapped around the fork it's easily moved to show high spots. Not perfect but works for me

i have a rear tire that will not seat perfectly on the bead it does this slight wobble been riding it as a xc bike didn't do much to fix it. I am getting a new bike soon. Ive checked the wheels for trueness and they are its just the tire. it could be mis molded or it could be not sitting on the rim perfectly. put a zip tie with the leader touching the rim on the seat stays spin the wheel check for wobble.

for mine, I deflate, massage & re-inflate. this improves the tire wobble I've had with my 2.25" WTB Riddlers. I've read about large MTB type tires having this kind of issue, so you're not alone

This works well most of the time! I also inflate them to max pressure afterwards, then back them off to riding pressure after a few minutes. I've had less tire/tube slippage on the rim due to hard braking after that practice. Dunno why.... maybe it seats the tire/tube better???

A couple of cm and you are not sure what is causing it, I like the "take it to the bike shop" suggestion. Then start looking for a new set of wheels.

Good luck.